Introduction

Voice Extensible Markup
Language (VoiceXML) is a markup language for creating voice user interfaces
that use automatic speech recognition (ASR) and text-to-speech synthesis (TTS).
The VoiceXML forum was formed in March 1999, by AT&T, IBM, Lucent and
Motorola to promote and to accelerate the adoption of VoiceXML-based
applications worldwide.<o:p />

Today, more than 10,000
commercial VoiceXML-based speech applications have been deployed across a
diverse set of industries, including financial services, government, insurance,
retail, telecommunications, transportation, travel and hospitality. Millions of
calls are answered by VoiceXML applications every day!<o:p />

Some of the things voice
xml was designed for and is being used today are creating audio dialogs, digitized
audio, spoken and DTMF key input recognition, spoken input recognition,
telephony and mixed initiative conversion.

Using the code

Consider an example
below. The first one is a simple "Hello, This is Keshav!".<o:p />

The
<vxml> element is a container for dialogs which is of two types, forms
and menus. Forms present menus and gather relative information while the menus
offer choice as to what must be done next. In the above example, it simply
presents "Hello, this is Keshav!" to the user. The conversation ends here since
there is no successor dialog presented by the form.

This
example asks the user for a choice of coffee and accordingly submits it to a
server script. A typical interaction between a computer (C) and a human (H)
would be, <o:p />

C: Would
you like to have espresso, Cappuccino, Mocha or nothing?<o:p />

H: <st1:city w:st="on"><st1:place w:st="on">Darjeeling tea.<o:p />

C: I did
not understand what you said.<o:p />

C: Would
you like to have espresso, Cappuccino, Mocha or nothing?<o:p />

H: Mocha.<o:p />

C: (continues
in document coffee2.asp)<o:p />

Architectural model

The
architectural model of voice xml considers the following components.

<o:p /> 1) A document Server

2) VoiceXML interpreter

3) VoiceXML interpreter Context

4) Implementation Platform.

A
document server processes requests from a client application, the voiceXML
interpreter through the voiceXML interpreter context. The server produces
voiceXML documents in reply which are produced by the voiceXML interpreter.<o:p />

The
voiceXML interpreter context may monitor user inputs in parallel with the
voiceXML interpreter. The implementation platform is controlled by the voiceXML
interpreter context and by the voiceXML interpreter. It generates events in
response to user actions and system events

Goals

VoiceXML's
main goal is to bring the full power of web development and content delivery to
voice response applications and to free the authors of such applications from
low level programming and resource management. It enables integration of voice
services with data services using the familiar client-server paradigm.<o:p />

Promotes service portability
across implementation platforms. VoiceXML is a common language for content
providers, tool providers and platform providers.<o:p />

Is easy to use for simple
interactions and yet provides language feature to support complex dialogs<o:p />

A possible shortcming

While
VoiceXML strives to accommodate the requirements of a majority of voice
response services, services with stringent requirement may be best served by
dedicated applications that employ a finer level of control.

Conclusion

VoiceXML is a promising
option in current and the future ages. To know more about VoiceXML forum and
the membership, visit http://www.voicexml.org<o:p />

License

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